There's another Abu Dawud hadith that says children buried alive are in Paradise:
Narrated Hasana' daughter of Mu'awiyah: She reported on the authority of her paternal uncle: I asked the Prophet (ﷺ): Who are in Paradise? He replied: Prophets are in Paradise, martyrs are in Paradise, infants are in Paradise and children buried alive are in Paradise.
We know that the phenomenon of children being unjustly buried happened during the days of ignorance under the Mushrikeen (polytheists), a practice later stopped by Islam and never carried out by Muslims. The children of polytheists who die as babies are going to be tested during the afterlife. Some will pass and go to Paradise, some will fail and go to Hell.
As per my own personal ijtihad (disclaimer: I am not a scholar), the above applies here too and is how the two narrations are reconciled. The ones who passed are likely mentioned in the hadith I quoted, the ones who fail are likely mentioned in the hadith you quoted.
Note: Of course, others explain the hadith you quoted by saying it's for a specific case and not general, or other explanations such as it's referring to the mother and the one who assisted the mother, or that the "girl" referred to reached puberty and agreed to it [similar to how some women in India used to kill themselves when their husbands died (aka satee)], etc. These are some of the explanations I have heard.
Islam is fair and just to everyone. Not a single soul will be wronged.